HeyItsNatalie wrote:Well that screams dust to me. People have been talking about achromacity in the spectrum, but remember we're looking for percent level differences. Those are hard to find in spectroscopy since we're diving up the light into so many little bins with only a few photons, the uncertainty will be larger in each. Subtle color changes are easier to find in photometry.

The transit at ~700 days in the Kepler data was caused by a ringed massive planet. The transit at ~1500 days is from a cloud of trojan asteroids in the same orbit as the object responsible for the event at ~700 days. In this scenario, the dip in brightness that happened last weekend is a secondary eclipse, where the planet+rings passed behind the star. If this is the case, the planet is on a 12-year orbit at 6 AU from the star. We can expect a series of transits to occur in 2021 as the leading trojan cloud transits the star. Then in 2023, the planet itself should transit.

The Trojans paper has been updated, now suggesting that the recent dip may be related to a population of Hilda-analogues. Presumably this is because the secondary eclipse explanation doesn't work.

Within our model, the timing of this event would correspond approximately to the point of opposition of the main body, therefore the corresponding L3 point would be passing in front of the star at this time. In this scenario, this dimming event could be explained by the effect of objects akin to the Hildian asteroids in the Solar System passing through L3. If what we have identified as Trojan asteroid regions are really so populated, in principle one could expect also a rather high population of Hildas. In this case, we would expect a few dimming events concentrated around the time when L3 transits in front of the star. This concentration of events would be, in any case, much fainter than the complex event at D1500 caused by the passage of the Trojans.

Detection of a repeated transit signature in the light curve of the enigma star KIC 8462852 : a 928-day period ?

As revealed by its peculiar Kepler light curve, the enigmatic star KIC 8462852 undergoes short and deep flux dimmings at a priori unrelated epochs. It presents nonetheless all other characteristics of a quiet 1 Gyr old F3V star. These dimmings resemble the absorption features expected for the transit of dust cometary tails. The exocomet scenario is therefore most commonly advocated. We reanalyzed the Kepler data and extracted a new high-quality light curve to allow for the search of shallow signature of single or a few exocomets. We discovered that among the 22 flux dimming events that we identified, two events present a striking similarity. These events occurred 928.25 days apart, lasted for 4.4 days with a drop of the star brightness by 1000 ppm. We show that the light curve of these events is well explained by the occultation of the star by a giant ring system, or the transit of a string of half a dozen of exocomets with a typical dust production rate of 10 5 -10 6 kg/s. Assuming that these two similar events are related to the transit of the same object, we derive a period of 928.25 days. The following transit was expected in March 2017 but bad weather prohibited us to detect it from ground-based spectroscopy. We predict that the next event will occur from the 3rd to the 8th of October 2019.

Bourne, Gary & Plakhov "Recent Photometric Monitoring of KIC 8462852, the Detection of a Potential Repeat of the Kepler Day 1540 Dip and a Plausible Model"https://arxiv.org/abs/1711.10612

Suggests the object is a >14 Jupiter masses brown dwarf on an orbit with eccentricity ~0.05, with a system of 9 rings extending out to 0.1 AU, tilted at 0.3°.

The authors are preparing another paper that will contain a detailed discussion of the system configuration, including possible satellites of the proposed brown dwarf. This includes modeling of D792 and deconstruction of the D1519 and D1568 dips into individual transits of comas and dust clouds that could be produced by sublimation of icy moons.